This invention relates generally to film used to wrap around products, and more particularly to a method and system of utilizing a roll of film having an overlap or lap seal.
Shrink film or film or thin sheeting used for wrapping a myriad of products in an unlimited number of configurations typically comes in two forms on a roll. The first form of film is known as flat sheeting that is typically used on expensive form, fill, and seal (FFS) machines that have high output capability. The resultant seal from an FFS machine is a lap seal that is easy opening. The second form of film comes on a center folded roll of film that is typically used on less expensive xe2x80x9cLxe2x80x9d sealer machines with less output capability than the FFS machines. The resultant seal from an L sealer machine is a xe2x80x9ctrimxe2x80x9d seal.
An industrial FFS machine costing approximately $50,000 could wrap approximately 80 to 100 products per minute. An FFS machine will typically dispense flat sheeting towards a forming device which folds the film on to itself with a slight overlap that is then typically sealed in a first direction utilizing a drag wire, hot melt, static points or some other sealing means to create a centered overlap seal. The item being wrapped is then inserted into the folded lap sealed xe2x80x9cenvelopexe2x80x9d and then finally sealed in a second direction (perpendicular to the overlap seal) typically using a sealer in the form of a heated bar that serves to both side seal the bottom side of the wrapping for the first item and side seal the top side of the wrapping for the next item. The heated side bar coincidentally also serves as a cutting mechanism to separate the first wrapped item from the next xe2x80x9cenvelopexe2x80x9d which will soon include another item formed from the next portion of flat sheeting that has been dispensed. To remove the air and form a tight wrapping around the item, the wrapped item can then be fed through a heated tunnel or shrink tunnel having a heat pump. The heat pump causes the shrink film to shrink or re-orient and thereby driving the air out from between the wrapping and the item through perforations or vent holes in the wrapping. The perforations in the wrapping can be created in many different ways as will be further discussed below.
The second form of shrink-wrap film as previously mentioned typically comes on a center-folded roll of film. In other words, the film on the roll is pre-folded in half. This folded film on a roll is typically used on an xe2x80x9cLxe2x80x9d sealer machine or an automatic xe2x80x9cLxe2x80x9d sealer with side sealer machine. An L sealer where items are inserted manually can typically wrap 15 to 20 items per minute while an L sealer with an automatic inserter could possibly wrap up to 40 items per minute. Another variation of L sealer with side sealer in an automated form can wrap up to 60 items per minute. In any event, the center folded roll of film is placed on a dispenser and fed through either side of a separator table. The dispenser (in either an FFS machine or L Sealer machine) will typically utilize a shaft and brackets on either side of the roll or alternatively a cradle with rollers where the roll of film is placed. The item is placed on either side of the separator table (either above or below the separator table) and between the folded roll of film. The xe2x80x9cLxe2x80x9d sealer bar which is a heated reverse xe2x80x9cLxe2x80x9d shaped bar (having already created a top side seal on the prior item) further serves to seal the prior item on two other sides and to form the top side seal on the next item. The L sealer bar only needs to create seals on three sides since the folded portion completes the sealed wrapping on a fourth side. The resultant trim seal from an L sealer can be evident on 3 adjacent sides of a rectangular object with the fourth adjacent side typically formed from the pre-folded film area.
The lap seal formed on an item from an FFS machine is easier to open than a trim seal from an L sealer machine. If an owner of an L sealer wraps for example cookies, muffins, or other non-rigid products with a trim sealed wrapping, it is very likely that the non-rigid product will crumble when trying to open the wrapping. A lap sealed wrapping would certainly reduce the chances of crumbling the non-rigid contents. Unfortunately, there is currently no way to form a lap seal on an L sealer machine using the center folded roll of film currently available. Thus, a need exists for a method of providing a lap seal using an L sealer machine. Furthermore, a need exists for a modified roll of film that will allow existing L sealer machines, other customized L sealer machines, or possibly other types of sealer machines to provide a lap seal on a shrink-wrapped item.
In a first aspect of the present invention, folded film used to create a lap seal using an L sealer comprises a first film folded substantially in a form of a xe2x80x9cJxe2x80x9d and a second film overlapping at least a portion of the first film, wherein the first film and the second film are coupled together in at least a portion of an overlapping area.
In a second aspect of the present invention, a method of forming film used to create a lap seal comprises the steps of providing a first film, applying a second film to overlap at least a portion of the first film, and coupling the first film to the second film in at least a portion of an overlapping area of said first and second films.
In a third aspect of the present invention, a method of shrink wrapping an item to form a lap seal using an xe2x80x9cLxe2x80x9d sealer machine comprises the steps of dispensing pre-folded film having a pre-existing lap seal on the pre-folded film onto a separator table of the L sealer machine, inserting an item between the separator table and a first side of the pre-folded film, and sealing the item on at least two sides using a substantially L-shaped heated bar forming a substantially wrapped item.
In a fourth aspect of the present invention, a method of forming film used to create at least one lap seal comprises the steps of providing at least a first film, applying a subsequent film to overlap at least a portion of the first film, and coupling the first film to the subsequent film in at least a portion of an overlapping area of said first and subsequent films.